The following is a tabulation of some prior art that presently appears relevant:
U.S. Pat.Pat. No.Kind CodeIssue DatePatenteeNo. U.S. 6,062,142May 16, 2000Atlantic ResearchCorp.No. U.S. 6,267,110Jul. 31, 2001ConvenienceHeating Tech. LTDNo. 20080115409May 22, 2008Tran Bo LNo. 20090025276Jan. 29, 2009Tran Bo LNon Patent LiteratureDocumentsNone
Fire has been an age's long requirement for comfort, safety, and security since the beginning of civilization. Earlier form of fire-starters has been in the form of converting a mechanical motion into heat generated by friction. Such examples are two flint stones striking each other, a fire bow drill whereby a stick is rotated rapidly in a hole using the bow to rotate it, and the modem matches. However, none of these mechanical motions would produce the necessary sparks or heat if friction was absent or was severely compromised. This friction based form of combustion, or more specifically the right level of Coefficient of Friction of two contacting surfaces, may not be available in the extreme environment the fire is being produced in, such as in high humidity places. Thus a self-contained fire-starter that bypasses the need for friction, that has almost all the necessary conditions for fire-starting, that has all these conditions contained in a portable unit that permits a long shelf life, is more conducive for fire-starting under unfavorable conditions.
One of the most visible forms of portable fire-starters bypassing friction is the chemical reaction between reagents. This chemical reaction is exothermic, providing sufficient heat release to raise the temperature of the exothermic activity so as to combust the fuel in the reagents and/or ancillary fuel adjacent to the exothermic activity.
It is common for exothermic reaction based fire to use a first group of reagents that includes at least one compound selected from the group consisting of potassium permanganate, manganese oxide, potassium chlorate, barium peroxide and potassium nitrate. It is also common to exothermically pair this first group of reagent with a second group of reagent that includes at least one compound selected from the group consisting of ethanol, isopropanol, ethylene glycol and polyethylene glycol. When these two groups of reagents are in admixed with each other, they produce an exothermic reaction releasing sufficient energy to combust the reagents themselves and/or ancillary fuel adjacent to the exothermic activity.
It is from this spontaneous and volatile nature of combustion that creates the challenge to keep these two groups of reagents safely, properly, and conveniently housed close to—but separate from—each other, ensuring the absence of an accidental activation of the exothermic reaction; to provide a quick, portable, and inexpensive means to selectively admix them; and to ensure the byproducts of such combustion will not limit or impede the use of this combination in a narrow and restricted way. This challenge is further made bigger by the fact that the first group of reagents is granular and amorphous in nature, that it is a powerful oxidant that is harmful for human contact, and that its potency is rendered useless when wet. Additional challenges appear when the second group of reagents is liquid in nature, requiring a non permeable membrane or container to prevent accidental admixing/combustion.
Aside from the safety considerations above, there has been an increasing appeal to have a self-contained fire-starter that is inexpensive enough to be used in starting a cooking grill, in starting recreational campfires, and even in providing instant fire for survivalist training/kits. This growing ubiquitous application for such tire-starter places a high premium for it to be produced inexpensively, with high portability, of high shelf life, of high reliability, and with as little intrusive by products that would deter its use:—all this while having a quick and uncomplicated means to start a fire instantly on demand.
In reference to a FIG. 7 embodiment as shown in Patent US 2010/0252023 A1 issued on Oct. 7, 2010 to Coffey et al, this embodiment does not meet the challenges of reliability, cost effectiveness, and of the difficult handling nature of the glycerin during its introduction into the device. It fails to properly avoid any accidental exothermic admixing of the reagents as the integrated piercing member 750 is placed over the entire system, putting the piercing member directly in line with the pathway that allows this admixing. This direct line of fire thus must heavily rely on the stiffness of the malleable material cover 760 to prevent this accidental admixing. But this stiffness-in-the-name-of-safety cover property is coupled to—in a way that also opposes—the ease in which the user can selectively deform the cover in order for the plunger to pierce the barrier 730. In short, Reliability and Ease of Admixing competes directly with each other.
Also in reference to the above FIG. 7 embodiment, the difficult handling nature of glycerin is not addressed. Glycerin is liquid in nature and is prone to leak where there is a micro breach in containing it. The FIG. 7 embodiment does not provide any multi-barrier insurance in the event the single foil seal that separates the reagents is compromised during the assembly package or during the settling nature post assembly.
Additionally, the amorphous form of a liquid requires the barrier walls to be in place so as to contain the liquid glycerin during assembly. It is to my best understanding that during the deformation of the dome, the interior space in which the glycerin resides is reduced, causing a rise in internal pressure. This increase in pressure places additional stress to the foil sealant as well as to the dome sealing to the cylinder walls. This pressure increase can also be due to changes in storage temperature. Hence, the accidental admixing of the reagents can happen by the accidental deformation of the dome during handling as well as changes in storage temperature. Any avoidance of these accidental causal factors drives up the cost of the sealant design and manufacturing, as well as the cost to test their performance within an acceptable operating range. The cost of liability avoidance has just increased due to this complication.
In summary, FIG. 7 embodiment works well on paper but not in real life for it relies heavily on a single seal barrier, rather than a multi barrier seal, to prevent accidental admixing; it has only one last defense, versus multiple defenses, that can be easily and accidentally defeated when the piercing member is in line with the piercing path that pierces the seal; the sealing chamber for the glycerin is prone to leaks caused by an accidental deformation of the dome and by uncontrollable changes in the storage temperature; and the stiffness of the malleable cover stiff enough to prevent any accidental deformation would oppose the ease of piercing the foil barrier.
In reference to the embodiment of FIG. 2C of U.S. Pat. No. 6,267,110 BI issued to Tenenboum on Jul. 31, 2001, Tenenboum employs a different implementation, starting with a liquid reagent contained in storage cell 16 as a foil packet. To provide controlled tearing of the packet on demand, foil packet 16 encloses a specially formed spring element 46. As best seen in FIG. 2C, spring element 46 is formed with a piercing element 48 and a number of resilient spacers 50 biased to a position in spaced relation to piercing element 48. In a normal un-flexed state of spring element 46, resilient spacers 50 prevent contact between piercing element 48 and foil packet 16. When force is applied through one surface of foil packet 16, spring element 46 is deformed such that piercing element 48 comes into contact with the opposite surface of foil packet 16 so as to tear open the foil packet and release the liquid reagent onto the first reagent in second region 14. Here too, the force required for actuation is preferably provided by relative movement of heating unit 10 relative to container 18.
Tenenboum's art again suffers the same reliability and cost effectiveness problems as in Coffey. With respect to reliability, the only last line of defense preventing accidental admixing of the reagents is in the prevention of heating unit 10 relative movement to container 18. That is because the piercing element 48 is in a biased space relation to the foil packet containing the liquid reagent. However, an accidental movement of heating unit 10 relative to container 18 removes this biased space, causing the unintended admixing of the reagent. A prevention of this would require a locking and confirmation device that user wants to move heating unit 10 relative to container 18. This drives the design to be more complicated and costly, which is already driven up by the spring element and the plurality of dividing walls and devices to perform selective communication between reagents.